Helminthiases / / August 12, 2017
Amoebiasis (Lat.), Amoebiasis, amoebic dysentery (Russian.), Amebiasis, amoebic dysentery (Eng.), Amibiase, dysenterie amibienne (fr.), Disenteria amebiana, loes-chiasis (App.).
Amebiasis - a protozoan disease characterized mainly ulcerative lesions of the large intestine and sometimes complicated amoebic abscesses of the liver, lungs, brain and other organs.Often there are subclinical forms.Carriage of amebiasis is widespread everywhere.Clinically expressed forms of amoebiasis are more common in tropical countries, in the republics of Central Asia and the Caucasus, but recorded in the temperate zones.
causative agent of amebiasis is the tissue-dissolving amoeba Entamoeba histolytica, exists in man in two forms - the vegetative and cystic.The cysts are formed in the gut of the vegetative forms of amoebas under adverse conditions.
Types amoebic forms
Among vegetative forms of amoebae are distinguished big vegetative, fabric, and luminal predtsistotnuyu form , having the morphological features assoc
Most vegetative tissue-dissolving form amoeba reaches a length of 15-40 m, and in the extended state - even 60-80 microns.When movement is clearly visible division into ectoplasm and glassy granular endoplasm.In the cytoplasm of amoebae are often found phagocytized erythrocytes.As a result, they have much less normal digestion.Characteristically amoebae movement, committed shocks, by suddenly formed pseudopodia, which grow in a certain direction by transfusion in their cytoplasm.Core amoeba spherical shape with a diameter of 3-7 microns.Most of the vegetative form of an amoeba found in the feces of sick amoebic dysentery, which ensures the accuracy of the diagnosis.
parasite in tissues of the so-called histological tissue amoeba. It reaches values of 20-25 microns, the cytoplasm and the nucleus in it are the same as in high vegetative amoeba, any inclusions usually not available.
luminal form dwells in the proximal part of the contents of the colons of healthy individuals.In structure it is close to a large vegetative form;its size of about 20 microns.Sometimes it penetrates the tissue.In the presence of lesions in the bowel amoebic she phagocytose red blood cells and increases in size.
In poluoformlennyh feces found slightly movable mold amoebae predtsistnye , often with the bacteria in the cytoplasm;size of 12-20 microns.The condensed feces amoeba movement stops, it is surrounded by a shell, turns into a cyst.Mature cysts have 4 cores with a diameter of 8-15 microns.
main source of infection source of infection is a person, with feces which are allocated amoeba cysts;the value of the animals is negligible.The feces at 13-17 ° C cysts remain viable for about 15 days at a temperature of 37 ° C -. Only 24 hours in vivo, at the soil surface, oscillating between 10 and 50 ° C, cysts die within 2-3 days.The vegetative forms of amoebas faeces can survive for 20-30 minutes.Amebiasis Infection occurs by ingestion of cysts E. histolytica with vegetables, fruits, some other food and water contaminated by the feces of the patient or tsistonositelya.
Pathogenesis and pathological anatomy
The pathogenesis of lesions of the large intestine with amoebiasis are mobility and the enzymatic effect of amoebae, which makes their introduction into the intestinal wall.Thus, in some strains of amoebae discovered the enzyme hyaluronidase, which has tissue-dissolving properties.Penetrating into the submucosa of the intestine, amoebae multiply.Near them occur exudation, infiltration and cell round coagulation necrosis of tissue with the formation of yellowish nodules.Recently opened in the lumen of the intestine, amebic ulcers formed in size from microscopic to several square centimeters.Form ulcers wrong, saped edge.The bottom of ulcers usually a submucosa, but sometimes even the muscular layer and serosa.The latter entails the formation of intestinal adhesions with the surrounding organs.In the wall of the intestine often arise hemorrhage.If amoebiasis is not combined with bacillary dysentery, the mucosa between the ulcers do not hyperemic.
- Amebiaz symptoms
- Perforation and colon gangrene when amebiasis
- Appendicitis with amoebiasis
Usually ulcers are located in the cecum and distal ascending colonintestine, often in direct and sigmoid colon, appendix, and in a few cases in the lower segment of the ileum.When healing them sometimes scar comes intestinal narrowing.
When amebiasis possible damage to the liver, lung, brain, skin and other organs and tissues as a result of hematogenous dissemination amoebae or their penetration of adjacent organs.In the liver, lung and brain abscess formation.In the first two bodies of pus usually yellowish-red or chocolate color, the brain - light gray.